FROM instruction tells webapp.io what base to use to run tests from.
There can only be one
FROM line in a Layerfile, and it must always be the
first directive in the Layerfile.
For now, only
FROM vm/ubuntu:18.04 is allowed as a top level, but inheriting
from other Layerfiles is possible.
FROM vm/ubuntu:18.04to use ubuntu:18.04 as the base.
FROM ../baseto inherit from the file at
../base/Layerfilerelative to the current Layerfile
FROM /baseto inherit from the file at
FROM webapp.io/rails:2.7.1to inherit from the shared Layerfile library configuration
FROM my-org/base:v1.0.0to inherit from a common image for your organization in the shared Layerfile library